松辽盆地王府凹陷断层特征及对油气的控制

通过系统分析断层形成和演化过程,研究松辽盆地王府凹陷断层对油气成藏的控制作用.将王府凹陷断层划分为4种类型,即断陷期伸展断层、坳陷期拉张断层、反转期挤压断层和长期活动断层.确定断层活动主要有3期:火石岭组至营城组沉积时期形成断陷期伸展断层；青山口组沉积时期形成坳陷期拉张断层；嫩江组至新近系沉积时期形成反转期挤压断层.研究结果表明:断层活动强度不同造成断陷期和坳陷期源岩有机质类型和砂体分布及类型存在差异.断陷期断层活动强度较大,有机质类型接近Ⅲ型,形成扇三角洲和辨状河三角洲等快速沉积；坳陷期断层活动强度较小,有机质类型趋向Ⅰ型,形成与长期活动断层平行的储集砂体；断层除作为油气垂向运移的通道外,与砂体组合成断层-岩性输导脊指示王府凹陷平面油气优势运移方向为NNE向和SSW向.

Characteristics of fault and its control on oil-gas in Wangfu Depression of Songliao Basin

Through analyzing the formation and evolution of faults in Wangfu Depression,the effect of fault on oil-gas reservoir forming was studied.The faults in Wangfu Depression are divided into four types,including the extensional faults of fault-depression stage,the tensional faults of depression stage,the compressive faults of structure reverse stage and the long-term moving faults.There are three primary periods of fault activity.During the sediment period from Huoshiling formation to Yingcheng formation the extensional faults were grown.In the sediment period of Qingshankou formation the depression faults were formed.In the sediment period from Sifangtai formation to Neogene the transpressional faults were formed.The results show that the different moving strengths of faults cause the different organic matter types of source rocks,and different distribution and types of sand bodies in fault-depression stage and depression stage.In fault-depression stage the moving strength of faults is bigger,organic matter of source rocks approaches type Ⅲ,and fan delta and braided channel delta sedimentary are formed.In depression stage the moving strength of faults is smaller,organic matter of source rocks reaches type Ⅰ,sand bodies paralleling to the long-term moving faults are formed.Besides as the pathway of oil-gas vertical migration,faults combined with sand into fault-lithology pathway ridge indicate that the preferred direction of migration is NNE and SSW directions in Wangfu Depression.